Error 0x800f0922 installing .NET 3.5 on Windows 8

I'm trying to install .NET 3.5 on my Windows 8 box and it keeps throwing Error 0x800f0922 at me. From what I've read on answers.microsoft.com and StackOverflow I gather the easiest way to fix this is to perform a system refresh, however this will remove all software I've installed from discs. I've just moved house, so I'd rather not do that as I don't know where all the installation media actually are for a lot of my software, so if possible I'd prefer to track down where the problem is actually occurring. (Also, I have a LOT of software installed. It'd take me a long time to reinstall it all, and I unfortunately haven't got that time.)

The on-demand error screen sends me to KB2734782, which doesn't help much.

When I run this DISM line from the StackOverflow post:

Dism.exe /online /enable-feature /featurename:NetFX3 /All /Source:C:\Windows\WinSxS /LimitAccess

I get the following output on the terminal:

Microsoft Windows [Version 6.2.9200]
(c) 2012 Microsoft Corporation. All rights reserved.

C:\Windows\system32>Dism.exe /online /enable-feature /featurename:NetFX3 /All /Source:C:\Windows\WinSxS /LimitAccess

Deployment Image Servicing and Management tool
Version: 6.2.9200.16384

Image Version: 6.2.9200.16384

Enabling feature(s)
[==========================100.0%==========================]

Error: 0x800f0922

DISM failed. No operation was performed.
For more information, review the log file.

The DISM log file can be found at C:\Windows\Logs\DISM\dism.log

C:\Windows\system32>

Incidentally, it jumps straight from 0 to 100% and then sits on that line for about 5 minutes before the error line occurs.

dism.log contains the following lines around that time: (Link to full logs is at bottom of post)

2013-07-02 00:56:58, Info                  DISM   DISM.EXE: Succesfully registered commands for the provider: Edition Manager.
2013-07-02 00:56:58, Info                  DISM   DISM Provider Store: PID=5768 TID=5780 Getting Provider DISM Package Manager - CDISMProviderStore::GetProvider
2013-07-02 00:56:58, Info                  DISM   DISM Provider Store: PID=5768 TID=5780 Provider has previously been initialized.  Returning the existing instance. - CDISMProviderStore::Internal_GetProvider
2013-07-02 00:56:58, Info                  DISM   DISM Package Manager: PID=5768 TID=5780 Processing the top level command token(enable-feature). - CPackageManagerCLIHandler::Private_ValidateCmdLine
2013-07-02 00:56:58, Info                  DISM   DISM Package Manager: PID=5768 TID=5780 Attempting to route to appropriate command handler. - CPackageManagerCLIHandler::ExecuteCmdLine
2013-07-02 00:56:58, Info                  DISM   DISM Package Manager: PID=5768 TID=5780 Routing the command... - CPackageManagerCLIHandler::ExecuteCmdLine
2013-07-02 00:56:58, Info                  DISM   DISM Package Manager: PID=5768 TID=5780 Encountered the option "featurename" with value "NetFX3" - CPackageManagerCLIHandler::Private_GetPackagesFromCommandLine
2013-07-02 00:56:58, Info                  DISM   DISM Package Manager: PID=5768 TID=5780 Encountered an unknown option "featurename" with value "NetFX3" - CPackageManagerCLIHandler::Private_GetPackagesFromCommandLine
2013-07-02 00:56:58, Info                  DISM   DISM Package Manager: PID=5768 TID=5780 Encountered the option "source" with value "C:\Windows\WinSxS" - CPackageManagerCLIHandler::Private_GetPackagesFromCommandLine
2013-07-02 00:56:58, Info                  DISM   DISM Package Manager: PID=5768 TID=5780 Encountered an unknown option "source" with value "C:\Windows\WinSxS" - CPackageManagerCLIHandler::Private_GetPackagesFromCommandLine
2013-07-02 00:56:59, Info                  DISM   DISM Package Manager: PID=5768 TID=5780 Initiating Changes on Package with values: 5, 7 - CDISMPackage::Internal_ChangePackageState
2013-07-02 00:56:59, Info                  DISM   DISM Package Manager: PID=5768 TID=5780 CBS session options=0x20100! - CDISMPackageManager::Internal_Finalize
2013-07-02 01:00:27, Info                  DISM   DISM Package Manager: PID=5768 TID=2420  Error in operation: (null) (CBS HRESULT=0x800f0922) - CCbsConUIHandler::Error
2013-07-02 01:00:27, Error                 DISM   DISM Package Manager: PID=5768 TID=5780 Failed finalizing changes. - CDISMPackageManager::Internal_Finalize(hr:0x800f0922)
2013-07-02 01:00:27, Error                 DISM   DISM Package Manager: PID=5768 TID=5780 Failed processing package changes with session options - CDISMPackageManager::ProcessChangesWithOptions(hr:0x800f0922)
2013-07-02 01:00:27, Error                 DISM   DISM Package Manager: PID=5768 TID=5780 Failed ProcessChanges. - CPackageManagerCLIHandler::Private_ProcessFeatureChange(hr:0x800f0922)
2013-07-02 01:00:27, Error                 DISM   DISM Package Manager: PID=5768 TID=5780 Failed while processing command enable-feature. - CPackageManagerCLIHandler::ExecuteCmdLine(hr:0x800f0922)
2013-07-02 01:00:27, Info                  DISM   DISM Package Manager: PID=5768 TID=5780 Further logs for online package and feature related operations can be found at %WINDIR%\logs\CBS\cbs.log - CPackageManagerCLIHandler::ExecuteCmdLine
2013-07-02 01:00:27, Error                 DISM   DISM.EXE: DISM Package Manager processed the command line but failed. HRESULT=800F0922

cbs.log has the following chunks around then which could be relevant:

2013-07-02 00:55:06, Info                  CBS    Exec: This is a PSF Package.  Job has been saved and we are returning to client.
2013-07-02 00:55:06, Info                  CSI    0000042d@2013/7/1:23:55:06.203 CSI Transaction @0xe2f5e59500 destroyed
2013-07-02 00:55:06, Info                  CBS    Exec: DPX job state saved for one or more packages, aborting the staging and install of execution.
2013-07-02 00:55:06, Info                  CSI    0000042e@2013/7/1:23:55:06.207 CSI Transaction @0xe2f5e58480 destroyed
2013-07-02 00:55:06, Info                  CBS    Perf: Stage chain complete.
2013-07-02 00:55:06, Info                  CBS    Failed to stage execution chain. [HRESULT = 0x800f0816 - CBS_E_DPX_JOB_STATE_SAVED]
2013-07-02 00:55:06, Info                  CBS    Failed to process single phase execution. [HRESULT = 0x800f0816 - CBS_E_DPX_JOB_STATE_SAVED]
2013-07-02 00:55:06, Info                  CBS    WER: Failure is not worth reporting [HRESULT = 0x800f0816 - CBS_E_DPX_JOB_STATE_SAVED]
2013-07-02 00:55:06, Info                  CBS    Reboot mark cleared

and further down:

2013-07-02 00:59:19, Info                  CSI    000004e6 Begin executing advanced installer phase 38 (0x00000026) index 253 (0x00000000000000fd) (sequence 289)
    Old component: [l:0]""
    New component: [ml:306{153},l:304{152}]"NetFx35CDF-CDF_GenericCommands, Culture=neutral, Version=6.2.9200.16384, PublicKeyToken=31bf3856ad364e35, ProcessorArchitecture=x86, versionScope=NonSxS"
    Install mode: install
    Installer ID: {81a34a10-4256-436a-89d6-794b97ca407c}
    Installer name: [15]"Generic Command"
2013-07-02 00:59:19, Info                  CSI    000004e7 Performing 1 operations; 1 are not lock/unlock and follow:
  (0)  LockComponentPath (10): flags: 0 comp: {l:16 b:19fc6600b776ce01c91f0000fc07a816} pathid: {l:16 b:19fc6600b776ce01ca1f0000fc07a816} path: [l:214{107}]"\SystemRoot\WinSxS\x86_netfx35cdf-cdf_genericcommands_31bf3856ad364e35_6.2.9200.16384_none_0cec490be12fb858" pid: 7fc starttime: 130171962799582915 (0x01ce76b5e2626ec3)
2013-07-02 00:59:19, Info                  CSI    000004e8 Performing 1 operations; 1 are not lock/unlock and follow:
  (0)  LockComponentPath (10): flags: 0 comp: {l:16 b:27236700b776ce01cb1f0000fc07a816} pathid: {l:16 b:27236700b776ce01cc1f0000fc07a816} path: [l:210{105}]"\SystemRoot\WinSxS\x86_netfx35cdf-csd_cdf_installer_31bf3856ad364e35_6.2.9200.16384_none_55072425fd5c3716" pid: 7fc starttime: 130171962799582915 (0x01ce76b5e2626ec3)
2013-07-02 00:59:19, Info                  CSI    000004e9 Calling generic command executable (sequence 1): [122]"C:\Windows\WinSxS\x86_netfx35cdf-csd_cdf_installer_31bf3856ad364e35_6.2.9200.16384_none_55072425fd5c3716\WFServicesReg.exe"
    CmdLine: [139]""C:\Windows\WinSxS\x86_netfx35cdf-csd_cdf_installer_31bf3856ad364e35_6.2.9200.16384_none_55072425fd5c3716\WFServicesReg.exe" /c /b /v /m /i"
2013-07-02 00:59:20, Info                  CSI    000004ea Performing 1 operations; 1 are not lock/unlock and follow:
  (0)  LockComponentPath (10): flags: 0 comp: {l:16 b:bd790401b776ce01cd1f0000fc07a816} pathid: {l:16 b:bd790401b776ce01ce1f0000fc07a816} path: [l:234{117}]"\SystemRoot\WinSxS\x86_microsoft.windows.s..ation.badcomponents_31bf3856ad364e35_6.2.9200.16384_none_353ccb4c94858655" pid: 7fc starttime: 130171962799582915 (0x01ce76b5e2626ec3)
2013-07-02 00:59:20, Info                  CSI    000004eb Creating NT transaction (seq 27), objectname [6]"(null)"
2013-07-02 00:59:20, Info                  CSI    000004ec Created NT transaction (seq 27) result 0x00000000, handle @0x24b8
2013-07-02 00:59:20, Info                  CSI    000004ed@2013/7/1:23:59:20.933 Beginning NT transaction commit...
2013-07-02 00:59:22, Info                  CSI    000004ee@2013/7/1:23:59:22.065 CSI    perf trace:
CSIPERF:TXCOMMIT;1387723
2013-07-02 00:59:22, Error                 CSI    000004ef (F) Done with generic command 1; CreateProcess returned 0, CPAW returned S_OK
    Process exit code 255 (0x000000ff) resulted in success? FALSE
    Process output: [l:28479 [4096]"DDSet_Entry: WFServicesReg.exe
DDSet_Status: CFxInstaller::CopyConfigFilesToTemp is64bit=0
DDSet_Status: CFileHelper::CopyConfigFilesToTempLocation
DDSet_Status: CFxInstaller::SetupBaseComponents isInstall=1
DDSet_Status: CFxInstaller::SetupBaseComponents Calling SetupExtensions. isInstall=1

(0x000000FF -- The extended attributes are inconsistent. ??)

And a bit further down:

2013-07-02 00:59:22, Error      [0x018007] CSI    000004f0 (F) Failed execution of queue item Installer: Generic Command ({81a34a10-4256-436a-89d6-794b97ca407c}) with HRESULT HRESULT_FROM_WIN32(14109).  Failure will not be ignored: A rollback will be initiated after all the operations in the installer queue are completed; installer is reliable (2)[gle=0x80004005]
[...snip...]
2013-07-02 00:59:22, Info                  CBS    Not able to add pending.xml.bad to Windows Error Report. [HRESULT = 0x80070002 - ERROR_FILE_NOT_FOUND]
2013-07-02 00:59:28, Info                  CSI    000004f1@2013/7/1:23:59:28.467 CSI Advanced installer perf trace:
CSIPERF:AIDONE;{81a34a10-4256-436a-89d6-794b97ca407c};NetFx35CDF-CDF_GenericCommands, Version = 6.2.9200.16384, pA = PROCESSOR_ARCHITECTURE_INTEL (0), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral;10609242us
2013-07-02 00:59:28, Info                  CSI    000004f2 End executing advanced installer (sequence 289)
    Completion status: HRESULT_FROM_WIN32(ERROR_ADVANCED_INSTALLER_FAILED) 
[...snip...]
2013-07-02 01:00:26, Info                  CBS    Exec: Cancelled pending transactions after rollback. [HRESULT = 0x00000000 - S_OK]
2013-07-02 01:00:26, Error                 CBS    Exec: An error occurred while committing the transaction, the transaction could not be rolled back. [HRESULT = 0x800f0922 - CBS_E_INSTALLERS_FAILED]

The full DISM and CBS logs are at http://ben.mu/files/dotnet35_dism_cbs.zip as the CBS log is nearly 167MB uncompressed. o.o dism.log gives the timeframe of where its errors occur--00:56:20ish to 01:00:22.

Does anyone have any ideas what's actually causing the installation to fail, and if so how I can fix it? Please don't just say "Refresh the OS". :)

Your source parameter is wrong. The files are removed from C:\Windows\WinSxS. You must point to the SxS folder on your mounted ISO/DVDdrive/USB thumb drive:

Dism.exe /online /enable-feature /featurename:NetFX3 /All /Source:DRIVELETTER:\sources\SxS /LimitAccess

Installing the .NET Framework 3.5 on Windows 8

http://msdn.microsoft.com/en-us/library/hh506443.aspx